Hydraulic fracturing is currently an important technique for accessing previously inaccessible hydrocarbon resources trapped within certain hydrocarbon-containing geologic formations. Hydraulic fracturing stimulates the flow of the hydrocarbon resource through fissures created in the formation and into the wellbore of a well drilled into the formation and results in enhanced recovery of the hydrocarbon resource relative to a similarly situated well created without the use of hydraulic fracturing.
A key technical difficulty is that the production rate of hydrocarbon resources from the formation decreases rapidly with time. This is believed be to be due in part to the susceptibility of the fissures to closure. In effort to restore the production rate and increase ultimate recovery of hydrocarbons from the formation, some operators restimulate wells by repeating the hydraulic fracturing treatment at additional locations within the wellbore. The restimulation treatment may be used to re-open closed fissures by pumping into existing perforations, or to hydraulically fracture new intervals of the formation which were not fractured initially, or both. Effective restimulation necessitates at least temporarily blocking perforations made in the well casing during an initial hydraulic fracturing of the hydrocarbon-containing formation.
Various perforation blocking techniques are currently available, diverting agents, coiled tubing intervention and expandable liners among them. Such currently available techniques suffer from one or more deficiencies, including unreliability and high cost and further advances in well restimulation are needed.